Clinical significance of matrix metalloproteinase-3 in systemic lupus erythematosus patients: a potential biomarker for disease activity and damage.

OBJECTIVES To assess the serum level of matrix metalloproteinase-3 (MMP-3) in systemic lupus erythematosus (SLE) patients and correlate it with clinical manifestations, laboratory findings, disease activity and damage. METHODS Forty-two female SLE patients were included in the present study. Full history taking, thorough examination and investigations were performed. Disease activity was assessed using the SLE disease activity index (SLEDAI). Furthermore, Systemic Lupus International Collaborating Clinics /American College of Rheumatology damage index (SLICC/ACR DI) was also assessed. Renal biopsy was done in those with lupus nephritis. Thirty age and sex matched subjects were included as control. Serum MMP-3 was measured by ELISA. RESULTS The mean serum MMP-3 level in SLE patients was significantly higher (80.9±45.8 ng/ml) than in the control (10.01±2.6 ng/ml) (p <0.0001). The level in patients with arthritis, nephritis or hematologic disorders were significantly higher than in those without (p<0.0001, p=0.02 and p=0.04 respectively). The MMP-3 was significantly different among the subclasses of renal biopsy (p=0.01) being higher in those with class IV (137.5±45.6 ng/ml). It significantly correlated with the SLEDAI, SLICC, white blood cells and platelet counts (r=0.37, p=0.02; r=0.36, p=0.02; r=0.32, p 0.04 and r=0.38, p=0.01 respectively). On linear regression analysis with age, disease duration and body mass index as independent factors, the SLEDAI and SLICC were not significant predictors. CONCLUSION Serum MMP-3 was found to be high in SLE patients and associated with arthritis, nephritis and hematological manifestations. Matrix metalloproteinase-3 correlated with disease activity and damage making it a possible biomarker and its measure of considerable interest related to the potential therapeutic responses and disease outcome.